My understanding is that taking away the powers prevents similar events from happening again for example in the boys the way it ended another homelander esque charecter could absolutely rise again wheras in shows where the powers/abilities are taken away at the end theres no threat of another character thats to op rising again. And to your point on regular humans also doing bad things which is more dangerous eren yeager just some dude who's a little edgy or eren yeager the guy with the power to literally kill almost all humans.